biol 302 introduction1 community and ecosystem biology biology 302
TRANSCRIPT
Biol 302 Introduction 1
COMMUNITY AND COMMUNITY AND ECOSYSTEM BIOLOGYECOSYSTEM BIOLOGY
Biology 302Biology 302
Biol 302 Introduction 3
Biol 302 Introduction 15
THIRD YEAR ECOLOGYTHIRD YEAR ECOLOGY
FALL Population ecology (BIOL 303)
SPRING Community ecology (& ecosystems)
• Community structure
• Succession
• Productivity
• Biodiversity
• Nutrient cycling etc.
Biol 302 Introduction 17
READINGS for this lecture series:READINGS for this lecture series:
KREBS cpt 20. The Nature of the Community
KREBS cpt 12. Pp 190 - 199
KREBS cpt 23. Predation & Competition (selected)
KREBS cpt 24. Disturbance Pp 485 - 501
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COMMUNITY ECOLOGY &COMMUNITY ECOLOGY & COMMUNITY STRUCTURECOMMUNITY STRUCTURE
Doing science at the community level presents daunting problems because data bases may be enormous and complex. Krebs Fig 23.4;
p464
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1. FIRST STEP is to DESCRIBE by searching for PATTERNS in community structure and composition.
• recognition of patterns is a big first step is all sciences.
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1. FIRST STEP is to DESCRIBE by searching for PATTERNS in community structure and composition.
• recognition of patterns is a big first step is all sciences.
2. Recognition of pattern leads to formulation of HYPOTHESES ABOUT THE CAUSES of the pattern
Biol 302 Introduction 22
1. FIRST STEP is to DESCRIBE by searching for PATTERNS in community structure and composition.
• recognition of patterns is a big first step is all sciences.
2. Recognition of pattern leads to formulation of HYPOTHESES ABOUT THE CAUSES of the pattern
3. Hypothesis testing by doing EXPERIMENTS or making further observations.
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THE NATURE OF THE COMMUNITYTHE NATURE OF THE COMMUNITY
Krebs: general read of cpt. 20Krebs: general read of cpt. 20
1. What is a community?
2. How to describe a community?
3. Does a community have boundaries?
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1. Is the community:· real?· abstraction?
2. Can you tell when you leave one community and enter another?
· prairie and deciduous forest of eastern USA (world map. Krebs p395 Fig. 20.6)· at Lytton on the Hope/Cache Creek Rd.
3. Or, do communities generally change
along some environmental gradient?
Biol 302 Introduction 25
1. Is the community:· real?· abstraction?
2. Can you tell when you leave one community and enter another?
· prairie and deciduous forest of eastern USA (world map. Krebs p395 Fig. 20.6)· at Lytton on the Hope/Cache Creek Rd.
3. Or, do communities generally change
along some environmental gradient?
Biol 302 Introduction 29
1. Is the community:· real?· abstraction?
2. Can you tell when you leave one community and enter another?
· prairie and deciduous forest of eastern USA (world map. Krebs p395 Fig. 20.6)· at Lytton on the Hope/Cache Creek Rd.
3. Or, do communities generally change
along some environmental gradient?
Biol 302 Introduction 30
Alternative models for vegetation organization along an environmental gradient (Krebs Fig. 20.5; p394)
Organismic concept
Individualistic concept
Resource partitioning model
Resource partitioning model with several layers
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Alternative models for vegetation organization along an environmental gradient (Krebs Fig. 20.5; p394)
Organismic concept
Individualistic concept
Resource partitioning model
Resource partitioning model with several layers
Biol 302 Introduction 32
Alternative models for vegetation organization along an environmental gradient (Krebs Fig. 20.5; p394)
Organismic concept
Individualistic concept
Resource partitioning model
Resource partitioning model with several layers
Biol 302 Introduction 33
Alternative models for vegetation organization along an environmental gradient (Krebs Fig. 20.5; p394)
Organismic concept
Individualistic concept
Resource partitioning model
Resource partitioning model with several layers
Biol 302 Introduction 34
Frederic Clements 1874 - 1945
Henry Gleason 1882 - 1975
Arthur Tansley 1871 - 1955
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CLEMENTS (1916, 1928)
ORGANISMIC CONCEPT
GLEASON (1926, 1927)
INDIVIDUALISTIC CONCEPT• Closely integrated system with birth, growth, maturation, development, death
– Homeostasis– Repair
• Random assemblages of species that happen to have same growth requirements
– They may interact
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CLEMENTS (1916, 1928)
ORGANISMIC CONCEPT
GLEASON (1926, 1927)
INDIVIDUALISTIC CONCEPT• Predictable development
• Climax– Predictable, stable– Convergence to sameness
• Randomness of seed dispersal, establishment etc.
• Climax – Disturbance prevents it– Different end points
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THE MODERN SYNTHESIS:THE MODERN SYNTHESIS:
• quite close to Gleason’s view of community structure and dynamics.
However, we do get some sharp boundaries:
• Environmental (Lytton)
• Soils
• Serpentine soils of northern Oregon
• Moisture
• Competition